The principal objective of the proposed research is the development of the coordination chemistry of copper(I) in order to provide model compounds of possible relevance to the structures and activity of the copper ion active sites in a number of redox active copper enzymes. The structural and chemical information from studies of new copper(I) chemical systems will then be utilized to establish the chemistry of derived analogous copper(I) compounds, and thus gain insight into the nature of the Cu(I)-Cu(II) redox process. The copper centers and enzymes of immediate interest are (a) the type 1 copper ion in the "blue" electron carriers and oxidases, (b) the type 3 copper center in the oxidase laccase, (c) hemocyanin and tyrosinase, and (d) dopamine beta-hydroxylase. A number of common features are apparent in the nature of the copper active sites of the proteins under discussion. They are: (1) the existence of "Cu(I)-like" sites in the proteins; (2) the reduced state of copper interacts/reacts with molecular oxygen in many of the copper enzymes. Specifically, our aims are to: (1) Design, synthesize and characterize new copper(I) coordination complexes of polydentate ligand systems. These will be both mononuclear and binuclear complexes, having primarily nitrogen and/or sulfur donor groups, and with coordination numbers of three and four. (2) Characterize analogous Cu(II) derivatives. (3) Examine and characterize the reaction chemistry of these copper complexes with reference to particular copper enzymes. Specifically, the interactions and reactions of the copper(I) complexes with molecular oxygen, biological substrates such as catechol and phenol derivatives, and electron transfer reactions are of interest.